1. Field of the Invention
The present invention is related to a high frequency CMOS dual/multi modulus prescaler.
2. The Prior Art
CMOS circuits are beneficial to system integration and are able to be formed on the same chip with low frequency circuits, and they are also able to decrease the consumption of circuit power. However, previous CMOS transistors have not been suited for use with bipolar junction transistors or GaAs transistors which are applied in a high frequency operational environment. Although production technology for transistors has been progressing, the operating frequency, which is up to 1 GHz, for the CMOS scaling divider is still an important challenge. And the need for this operating frequency is getting more necessary.
Mr. J. Yuan wrote a report in Electron. Lett., Vol. 24 pp.1311-1313 in 1988, which stated that CMOS transistors can be easily applied for digital dividers or digital counters, and it was an effective implementation. In his report in IEEE Solid-State Circuits, Vol. SC-24, pp. 62-70, 1989, Mr. Yuan wrote a report about applying True Single Phase Clock (TSPC) to CMOS circuits in a high frequency operating environment.
Although transistors, especially the previously stated CMOS transistors, which use TSPC circuitry, are able to operate in a high frequency environment, they have only been applied to single modulus dividers. However, the innovative high-frequency CMOS dual/multi modulus perscaler according to the invention uses TSPC circuitry for dual/multi dividers.
For conventional circuit construction, bipolar and GaAs circuits are the prescalers mainly used, while only a few use CMOS circuits. With CMOS circuits, the general design of dual modulus prescalers has been of one certain construction only. However, the invention includes a divide-by-3/4 or a divide-by-4/5 circuit applied in a dual and multi modulus, which is different from all other transistor circuits heretofore known.